The present invention relates to a new antibiotic designated as nanaomycin E and a process for producing the same.
Nanaomycin A is a known compound having antibiotic activity against Gram-positive bacteria, Trichophyton and Mycoplasma and may be used, for example, as antibacterial and therapeutic agents for humans and animals. Conventionally, nanaomycin A is produced by culturing a microorganism belonging to the genus Streptomyces and capable of producing nanaomycin A in a medium under aerobic conditions to accumulate nanaomycin A in the fermented liquor and nanaomycin A is recovered therefrom. A preferred strain for this purpose is Streptomyces rosa variant notoensis (FERM P-2209; ATCC 31135). The cultural and taxonomic characteristics of this strain are described, for example, in Japanese Patent Publication 24595/76; J. Antibiotics, 27, 363-365 (1974); ibidem, 28, 860-867 (1975); and ibidem, 28, 868-875 (1975). It is also known that by fermentation of this strain, nanaomycin B [Japanese Patent Publication 26514/76; J. Antibiotics, 27, 363-365 (1974); ibidem, 28, 868-875 (1975)], nanaomycin C [Japanese Patent Application as laid open to public inspection as Kokai Koho 133,986/77; J. Antibiotics, 28, 925-930 (1975)] and nanaomycin D [Japanese Patent Application 76589/76; J. Chemical Society, Chemical Communications, 9, 320-321 (1976)] may also be accumulated in the fermented liquor and may be recovered therefrom.
As shown by the following, nanaomycin B, C and D are structurally related to nanaomycin A and also exhibit antibiotic activities. Among them, nanaomycin A is believed to be the most useful for practical purpose because of its favorable activity, toxicity and stability. In this specification, nanaomycin A to E having the following formulas are referred to as nanaomycin-type compounds. ##STR2##